1. Technical Field
The present invention relates to an actuator, a light scanner, and an image forming device.
2. Related Art
As an actuator, there has been known one using a torsional vibrator (see, e.g., JP-A-2010-79243 (Document 1)). For example, Document 1 discloses a light deflector having a movable plate (a movable section), a support frame (a support section), and a pair of elastic support sections (connecting sections) for supporting the movable plate so as to be torsionally swingable with respect to the support frame, wherein each of the elastic support sections is formed of two rods (beam members).
Such movable plate, support frame, and pair of elastic support sections are formed integrally by anisotropically etching a silicon substrate having a principal surface constituted with a (100) plane of silicon.
Further, in the light deflector according to Document 1, the movable plate has an octagon shape in a plan view. The movable plate having such a planar shape has an advantage that the mass of the movable plate at the position distant from the axis of the swing can be reduced to thereby reduce the inertia moment.
However, in the movable plate having the octagon planar shape, there has been a problem that in the case of manufacturing the movable plate using the anisotropic etching described above, there occurs a large variation in shape due to the relationship with the crystal plane.